Stop printing images.caching.internal.knative.dev in kubectl get all (#43)
Stop printing images.caching.internal.knative.dev in kubectl get all (#43)

Currently `kubectl get all` outputs
`images.caching.internal.knative.dev`, but it is one of internal CRDs
and not necessary to examine the output in general.

This patch removes `all` from categories to stop printing
images.caching.internal.knative.dev in kubectl get all.
knative/caching,knative/caching